Method and system for wireless charging of implantable medical devices

Abstract

An RF charging system for implantable medical devices. The RF charging system includes a radio frequency (RF) signal, a first antenna configured to transmit the RF signal, a second antenna configured to receive the RF signal transmitted by the first antenna, tune characteristics of the RF signal, and improve power transfer with impedance matching circuitry, an RF to direct current (DC) converter configured to convert the RF signal of the second antenna into a DC signal, and a battery management circuit configured to receive the DC signal and provide voltage to a battery.

The invention claimed is: 
     
       1. A magnetic resonance imaging (MRI) lucent, wirelessly-chargeable, implantable medical device, comprising:
 an MRI-lucent housing; and 
 an MRI-lucent antenna contained in the housing and configured to wirelessly receive an electromagnetic signal from a signal source external to the housing, wherein the signal source further comprises: 
 a primary modulator configured to combine a raw signal with a carrier signal to provide a signal having continuous phase modulation; and 
 a secondary modulator configured to combine the signal having continuous phase modulation with a pseudorandom noise sequence to provide a signal having direct sequence spread spectrum modulation, wherein the signal having direct sequence spread spectrum modulation is input to an antenna of the signal source. 
 
     
     
       2. The implantable medical device of  claim 1 , wherein the electromagnetic signal is a radio frequency (RF) signal. 
     
     
       3. The implantable medical device of  claim 1 , further comprising a direct current (DC) converter contained in the housing and configured to convert the electromagnetic signal to direct current. 
     
     
       4. The implantable medical device of  claim 2 , further comprising a direct current (DC) converter contained in the housing and configured to convert the RF signal to direct current. 
     
     
       5. The implantable medical device of  claim 3 , further comprising a battery contained in the housing and chargeable by the direct current. 
     
     
       6. The implantable medical device of  claim 4 , further comprising a battery contained in the housing and chargeable by the direct current. 
     
     
       7. The implantable medical device of  claim 1 , wherein the device is implanted in an organism and the signal source is external to the organism. 
     
     
       8. The implantable medical device of  claim 1 , further comprising one or more of a reservoir, a sensor, an external outlet, and a catheter. 
     
     
       9. A wireless charging system for implantable medical devices, comprising:
 a wirelessly-chargeable, implantable medical device having an MRI-lucent housing and an MRI-lucent antenna contained in the housing; and 
 a signal source external to the housing; 
 wherein the antenna is configured to wirelessly receive an electromagnetic signal from the signal source; and the signal source further comprises: 
 a primary modulator configured to combine a raw signal with a carrier signal to provide a signal having continuous phase modulation; and 
 a secondary modulator configured to combine the signal having continuous phase modulation with a pseudorandom noise sequence to provide a signal having direct sequence spread spectrum modulation, wherein the signal having direct sequence spread spectrum modulation is input to an antenna of the signal source. 
 
     
     
       10. The wireless charging system of  claim 9 , wherein the electromagnetic signal is a radio frequency (RF) signal. 
     
     
       11. The wireless charging system of  claim 9 , further comprising a direct current (DC) converter contained in the housing and configured to convert the electromagnetic signal to direct current. 
     
     
       12. The wireless charging system of  claim 10 , further comprising a direct current (DC) converter contained in the housing and configured to convert the RF signal to direct current. 
     
     
       13. The wireless charging system of  claim 11 , further comprising a battery contained in the housing and chargeable by the direct current. 
     
     
       14. The wireless charging system of  claim 12 , further comprising a battery contained in the housing and chargeable by the direct current. 
     
     
       15. The wireless charging system of  claim 9 , wherein the device is implanted in an organism and the signal source is external to the organism. 
     
     
       16. The wireless charging system of  claim 10 , the signal source further comprising a tracking system configured to direct the RF signal emitted by the signal source towards the antenna of the implantable medical device. 
     
     
       17. A method for wireless charging, comprising:
 wirelessly transmitting an RF signal from a signal source; and 
 receiving the RF signal with a magnetic resonance imaging (MRI) lucent antenna that is contained in an MRI-lucent medical device housing; 
 wherein the signal source is external to the housing, and further comprises a primary modulator configured to combine a raw signal with a carrier signal to provide a signal having continuous phase modulation; and 
 a secondary modulator configured to combine the signal having continuous phase modulation with a pseudorandom noise sequence to provide a signal having direct sequence spread spectrum modulation, wherein the signal having direct sequence spread spectrum modulation is input to an antenna of the signal source. 
 
     
     
       18. The method of  claim 17 , further comprising directing the RF signal emitted by the signal source towards the antenna. 
     
     
       19. The method of  claim 17 , wherein the housing is implanted in an organism and the signal source is external to the organism.